Extensible piston-ring.



No. 703,590. Pat ented July I, I902.

0. JOHNSON.

EXTENSIBLE PISTON RING.

4 (Application filed May 25, 1901.) (No Model.)

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UNITED STATES PATENT OFFICE.

OTTO JOHNSON, OF BROOKLYN NEW YORK.

EXTENSIBLE PISTON-RING.

SPECIFICATION forming part of Letters Patent NO. 703,590, dated July" 1, 1902.

Application filed May 25, 1901.

To all whom it may concern.-

Be'it known that I, OTTO JOHNSON, of the borough of Brooklyn, New York, N. Y., have invented a certain new and useful Improvement in Extensible Piston-Rings, of which the following is a specification.

This invention consists of a circumferentially-extensible piston-ring, means for applying elastic pressure thereto in a direction tending to circumferentially extend it, and a locking device for taking up such elastic pressure when the piston-ring has acquired a close sliding fit with the cylinder, whereby the piston-ring may thereafter reciprocate without exerting the radially-outward pressure upon the wall of the cylinder, which is the cause of the wear of cylinders and piston-rings as ordinarily constructed.

The accompanying drawings, illustrating the invention, are as follows:

Figure 1 is a piston-ring composed of two segments constructed with rabbeted slipjoints and with two sets of expanding-springs and two locking devices presenting abutments for taking up thethrusts of the springs respectively. Fig. 2 is a View representing on a larger scale than Fig. 1 the details of construction of one of the. rabbeted slipjoints, the system of expanding-springs, and its locking device for limiting the range of circumferential extension of the packingring. Fig. 3 is an elevation showing a portion of the periphery of the ring atone of the joints. Fig. 4 is an isometrical perspective of a group of superposed liners. Fig.- 5 is an elevation showing the arrangement of the system E of expanding-springs in the cell D.

The main piston-ring embodying the present invention may be made in one piece it intended for use with cylinders of moderate diameter or may be made with any desired number of segments when made for use with cylinders of large diameters. Thus Fig. 1 represents a piston-ring made of two segments A and B, connected by two rabbeted slip-joints.

It will be understood that for a small cylinder one of the rabbeted slip-joints shown in Fig. 1 will be omitted and the main part of the piston-ring be made of a single piece of metal. As the rabbeted slip-joints are Serial No. 61,827. (No model.)

alike in construction, the subjoined description of one ofthem will suffice. It maybe assumed that Fig. 2 represents the rabbeted slip-joint as connecting the adjacent ends of two segments A and B. The rabbeted joint is composed of the relatively short underlapping member formed of the inward offset a of one end of the segment A and the relatively longer overlapping member I), constituting an extension of the adjacent segment B.

On its inner side the overlapping member I) is provided with an inwardly-projecting boss 19, having a thickness in a radial direction corresponding to the thickness in a radial di rection of the underlapping member a. A locking-bar 0, bearing upon the concave faces of the member a and the boss b, is secured to the main segment A and the main segment B by the screw-bolts c and c, which are inserted through slotted apertures in the offset portions 0 and c of the locking-bar c. The space within the locking-bar c and between the extremity of the underlapping member a and the boss b constitutes the cell D for containing the system E of expanding-springs,

the action of which tends to extend the pis ton-ring circumferentially. The preferred construction of these springs is that illustrated in Figs. 2 and 5. As shown, each spring e is made of aflat ribbon of steel bent approximately into the form of' an ellipse. Any desired number of these springs can be forced into the cell D. The thrust of the system of springs against the extremity a of the inwardly-offset underlapping member a is taken up by the undercut joint a between the opposed extremityof the ofiset underlapping member a and the outw'ardly-offset portion 0 of the locking-bar c.- The thrust of the springs in" the opposite direction is delivered against the end 1) of the boss 19 and is taken up by the system F of liners, which are shown as introduced between the undercut end I) of the boss b and of the correspondingly-inclined shoulder c of the outwardly-offset portion 0 of the lockingbar 0.

It will of course be understood that some or all of the liners may be introduced into the undercut joint a without altering the re sult or departing from the invention.

What is claimed as the invention is- 1. A rabbeted slip-joint for connecting the meeting ends of a circumferentially-extensible piston-ring, the said joint composed of a relatively long overlapping member provided with an inwardly-projecting boss; and an inward oifset forming a relatively shorter underlapping member; an expanding-spring system interposed between said boss and the 0pposed end of the said inward offset forming said underlapping member; a locking-bar provided upon its radially outward face with a recess for receiving said boss and said inward ofiset; a system of liners appropriately introduced into said recess for limiting to a prescribed extent the circumferentiallyexpanding influence of said spring system upon the members of said joint.

2. In a circumferentially-extensible pistonring, a rabbeted slip-joint; an expandingspring system tending to separate the members of said rabbeted joint in such direction as to circumferentially extend said pistonring; a locking-bar provided upon its radially-outward side with a recess having oppositely-undercut ends, presenting bearingfaces parallel with correspondingly undercut faces formed respectively upon the inwardly-offset underlapping member of said joint and upon a boss projecting inwardly from the overlapping member of said joint, and a prescribed number of liners introduced into one or both ends of said recess for the purpose of taking up the elastic pressure of said expanding-spring system and thereby relieving the piston-ring therefrom.

3. In a piston-packing, the combination of a divided and circumferentially-expansible piston-ring, means for exerting elastic pressure on said ring to expand the same to fit a surrounding surface, a locking-bar joining the ends of the divided ring, and means adapted to be interposed between the lock-' ing-bar and an end of the expansible pistonring to limit the action of the elastic expanding means and relieve the surface of further expanding pressure when the fit between the ring and surface has been secured.

4. In a piston-packing, the combination of a divided and circumferentially-expansible piston-ring, means for exerting elastic pressure on said ring to expand the same to fit a surrounding surface, a locking-bar joining the ends of the divided ring, and removable liners adapted to be interposed between the locking-bar and an end of the expansible piston-ring to limit the action of the elastic expanding means and relieve the surface of further expanding pressure when the fit between the ring and surface has been secured.

5. A piston-packing comprising a circumferentiallyexpansible piston-ring having a slip-joint, an expanding-spring system interposed between the abutments of said joint to circumferentially expand the ring to fit a surrounding surface, a locking-bar secured to both members of the slip-joint, and removable liners coacting with said locking-bar to limit the expanding action of the spring system and lock the ring against further expansion when the fit between the ring and the surrounding surface is secured.

OTTO JOHNSON. Witnesses:

A. M. J ONES, E. GATTERER. 

